It’s no nutritional secret that we need sufficient water daily and most of us know we ‘should drink more’, but why? And with so many options, what type of water should we drink?

Over 75% of the human body is water, it bathes each cell and facilitates the exchange of minerals, enzymes, nutrients and waste material in and out of the cell. It has a critical role for every function in the body and increasing your intake to a safe and recommended level of 2 litres daily for an adult (child volume varies on age, gender and activity) can have a host of positive effects including

Health benefits of water

  • Improved digestion – water is needed to make stomach acid and digestive enzymes to fully digest food.
  • Decreased tendency to constipation – not drinking enough fluid causes dry, hard faeces and constipation.
  • Relieves fatigue – this is often the first sign of dehydration…not thirst. Low fluid levels can alter your blood volume and make Supports mood balance and mental clarity – even a one to two percent drop in hydration levels can negatively affect your mood and your ability to think clearly.
  • Supports reduction of headaches and migraines – studies show an overall decrease in the frequency and intensity of some headaches and migraines when optimal hydration is reached.

Types and quality of drinking water

So we know that drinking more water will have a big impact on health. But with such variation in quality, what’s the best type of water to choose?

Tap water
Water quality varies throughout the UK, but tap water is always treated with chlorine to kill bacteria and make it safe to drink. Even so, it could contain residues of pesticides, herbicides and oestrogens that have made their way into the water supply. Your local water company may have information on their website about the exact composition and treatment methods of their water. On the plus side, tap water is cheap, easily available and needs no packaging.

Bottled water
Bottled water is losing popularity due to concerns about single use plastics, as well as the fact that chemicals from plastic can contaminate the water itself, particularly if not stored carefully. Be aware that the quality of bottled water also varies widely as all brands are different. Fossil fuels are also used in transportation to supermarket shelves; however it is convenient, and choosing glass bottles may be a better option than plastic.

Jug filters
These remove contaminants and impurities including chlorine, some heavy metals, bacteria and parasites, and possibly fluoride and oestrogens, depending on the filter selected. Some are costly while others work out cheaper in the long run than bottled water, as well as being more environmentally friendly. The filters need changing regularly, as per the manufacturer’s advice.

Activated charcoal sticks
For those tight on space, activated charcoal can be added to a jug or water bottle to remove contaminants such as chlorine and some heavy metals. This method has been used to purify water in Japan since the 17th century. The porous surface attracts contaminants found in tap water, which are then held on the surface of the carbon. They are not as quick as jug filters but are non-toxic, tasteless, last several months and can be composted in the garden.

Reverse osmosis
Reverse Osmosis (RO) is a filtration method which uses a special membrane to remove contaminants from water. It is usually fitted under a sink along with an activated charcoal filter to remove chlorine. RO is very effective at removing contaminants including heavy metals, asbestos and fluoride, however a lot of water is wasted in the process and useful minerals like calcium and magnesium are also lost. Some people add liquid minerals to the water afterwards, however this increases the cost. 

Distilled water
Distillation uses heat to turn water to steam. The steam rises and moves to a cooling chamber where it condenses back into liquid, leaving behind many of the contaminants. Distillation kills bacteria and reduces the presence of large particles including fluoride and heavy metals, but does not remove oestrogens since they vaporize with the water and rise with the steam. This method also removes some desirable minerals from the water.


Since drinking clean water is one the most important things you can do for your health, having a reliable and healthy source of water should be at the top of your priority list.

There are plenty of options out there, but what you choose is likely to be a balance between what you can afford, practicality, and whether you main concerns are health or environmentally driven.

Recommended reading: Batmanghelidj F, Your Body’s Many Cries for Water

The average adult human body is 50-65 percent water.